1. Field of the Invention
This invention pertains in general to searching collections of data and, in particular, to ways of querying such collections of data.
2. Description of the Related Art
The World Wide Web and other information storage and retrieval systems contain a great deal of information. With the advent of search engines and other similar tools it has become relatively easy for an end-user to locate particular information. For example, one can obtain a wealth of information about “elemental particles” by simply searching for the terms “elemental particles” on the Web. This search can be accomplished using one or both of a graphical search engine or a text-based search engine.
Many search engines exist to search the World Wide Web. The Google search engine, for example, employs a user-friendly syntax that lets users simply type in a search query for items of interest (e.g., typing “Britney Spears” to find out information about the singer Britney Spears). The Google search engine also allows users to construct more complex search queries. For example, advanced Google search allows users to search for web pages by specifying that the web page: a) must contain an exact phrase (by placing the query terms in quotes); b) must contain one or more of the query terms, or c) must not contain one or more of the query terms. This advanced search capability allows a user to tailor his search for web pages that contain specific information. Google search permits search of web pages, which are an example of unstructured data.
Many search engines also exist to search more conventional databases of structured data. For example, the SQL query language allows users to search more conventional structured databases. Such databases usually have data stored in predefined formats and in predefined fields. Thus, an SQL query looks for certain values in predefined fields.
As the retrieval and storage of information on the Internet continues to evolve, information is being stored in many different formats besides web pages. What is needed are new and advanced ways of searching large collections of data from diverse sources, such as the Internet.